Ever since he made the masterful 1988 documentary “The Thin Blue Line,” a film that made such a convincing case for the innocence of a man who landed on death row for the murder of a Texas police officer that it resulted in his being cleared of all charges and released from prison, several of the films of Errol Morris have delved into the nature of truth and just how slippery it can be--1999’s “Mr. Death: The Rise and Fall of Fred A. Leuchter Jr.” gave us an unforgettable look at a former designer of execution machines whose life took some unexpected turns when he began a sideline gig as a scientific advisor for Holocaust deniers that found him “proving” that the gas chambers at Auschwitz never existed and the 2003 Oscar-winner “The Fog of War” showed us, through the eyes of former Secretary of Defense Robert S. McNamara, just how elusive and easily manipulated the truth can be and the terrible human cost that can result from such manipulations. The notions of truth and the near-impossibility of ever really getting to know the truth about anything, even with the aid of eyewitness testimony and photographic evidence, are at the center of his latest film, the Iraq war documentary “Standard Operating Procedure,” and through his decidedly idiosyncratic filmmaking style, he has once again provided us with a fascinating contemplation of the subjects of truth and memory that will hit equally hard for viewers regardless of their place on the political spectrum.

The central subject of the film is the Abu Ghraib detainee camp in Baghdad and, more specifically, the photos of prisoner abuse that shocked the world when they were made public a few years ago. At the time, it was largely decided in the mind of the public that the atrocities depicted in those photos were simply the work of a few bad apples stationed there who were summarily court-martialed and dishonorably discharged for their actions--this was the notion put forth by the government and the media found no reason to question it. However, in the rush to find someone to blame for the misdeeds seen in those photographs, no one in the media bothered to take a closer look at either the photographs or the people who either took or appeared in them in order to find out who they were, why they did what they did and what was really going on in those photographs both inside and outside of the frame. Instead, Morris has taken it upon himself to do that here by gathering all the photographs, arranging them into a chronological timeline in order to provide some context and to interview five of the seven American soldiers involved with the abuses and photographs (the other two are still in prison and were not allowed to be interviewed) to explain what was really going on in those photos that everyone saw and what was happening outside of the frame that no one but them saw.

From their point-of-view, their actions were nothing more than the natural outgrowth of a group of poorly trained and poorly disciplined soldiers who were under the impression that they were merely softening up detainees for interrogations to come and that many of the most shocking things that were depicted in those photographs were less repellent forms of torture and dehumanization devised solely in their sick little minds and more the standard tactics now being sanctioned by high-ranking government and military officials to extract information even if such methods rarely result in any truly useful information. Whether you take their words at face value or as the desperate justifications of a group of people who were caught doing horrible things and are desperately trying to place the blame for what transpired on anyone but themselves is, of course, up to you. However, while Morris himself doesn’t let the soldiers completely off the hook (although one of the two not interviewed, Charles Graner, is painted by most of the others as both an all-around manipulative jerk and a key instigator of what followed), he does allow the accused to defend themselves in a more detailed and articulate manner than they were allowed to when the case first broke and his real anger seems to be directed less towards these low-level players and more towards the higher-ranking officials who condoned such behaviors and yet managed to walk away from the scandal virtually unscathed while the others were left holding the bag.

Considering that Morris’s previous films have, for the most part, dealt with subjects that most audiences had probably never even dreamed of, let alone considered to be worthy of depicting on screen--his stunning 1978 debut “Gates of Heaven” offered an eye-opening look at the people who ran and used a couple of California pet cemeteries and 1997’s “Fast, Cheap and Out of Control” offered glimpses into the lives and obsessions of a lion tamer, a topiary gardener, a robotics expert and a guy who dedicated his life to the study of naked mole rats--it may seem strange to find him turning his focus towards a broad subject that has already been explored in any number of documentaries that have emerged in the last few years. However, as those who have seen Morris’ past films can attest, his films are not like those made by any other documentarian currently working today and his now-familiar filmmaking tactics--such as the use of brief recreations of certain events (a bullet casing hitting the ground, an exploding helicopter, a hideous swarm of ants) used to help put us in the mindset of the person being interviewed, a hypnotic musical score (this time around, Danny Elfman fills in for regular Morris collaborator Philip Glass) and, most importantly, his innovative Interrotron camera system (a device that allows the interviewer and interviewee to look at each other without the interference of the camera apparatus, resulting in an unusually intimate image that feels as if the people talking are looking directly into the eyes of the audience while telling their stories)--and his general refusal to rely on such standard documentary devices as voice-over narration or news footage results in a film that makes you feel as those you are looking at the subject of prisoner abuse in Abu Ghraib for the very first time. The idea of training his focus on the photographs themselves is also a nifty entry point because by pointing out how easily the seemingly objective truth can be manipulated by whomever is telling the story, he is subtly reminding us that nothing--not the photographs, not the accounts of the soldiers or their superiors, not even the film we are watching--should be taken completely at face value and that viewers and reporters need to be constantly vigilant in order to differentiate between what is being presented as having happened and what really happened.

I must admit that while “Standard Operating Procedure” is an excellent movie, it is neither the best documentary on the subject of Iraq that I have seen (those would include Charles Ferguson’s “No Exit in Sight” and Alex Gibney’s “Taxi to the Dark Side,” the latter of which covers some of the same ground seen here) nor is it Morris’ best work as a filmmaker (the pacing seems a little off at times and as a result, it feels much longer than its 2-hour running time). And yet, it remains an uncommonly powerful film from an uncommonly powerful filmmaker that refuses to take the easy way out (by indulging in cheap shots or condescension) and challenges viewers by urging them to begin asking questions for themselves instead of relying on the media for easy answers. These are bold moves in the service of a bold movie, one that is likely to outrage and provoke anyone who comes into contact with it.